Not applicable.
Not applicable.
The invention relates to a device for stacking flat postal articles, in particular large-format, thick and rigid postal articles, in an upright position on a stack receiver, consisting of a base with a supporting wall and a support which can be displaced in the direction of the stack and which is provided for holding the stack of postal articles.
Particularly for use in course-sequence sorting machines, i.e. for the repeated return of postal articles and the separation of a stack of postal articles, a high stacking quality suitable for machine operation (edge alignment of the postal articles) is necessary.
A stacker is known which uses a rotating helical coil to feed horizontal postal articles to a stack of horizontal postal articles at the end of the helical coil (U.S. Pat. No. 5,562,399). This stacker is not suitable for stacking upright postal articles of different formats and different thicknesses and rigidities, because the different-sized postal articles can jam in the helical coil and not be securely fed.
Known sorting machines for flat, large-format postal articles do not sort in a stacker that arranges the articles in a guided manner, but instead into a container by an ejection process. This normally produces a stack of postal articles in which the alignment of the articles is limited (WO 95/02467).
A solution is certainly known whereby large letters in a very wide format range are ejected into specially-shaped stacking compartments to achieve a very high stacking quality (DE 198 05 562 C1). However, only small stacks approximately 150 mm high are formed in these compartments, and they have to be removed manually. The throughput is also very low due to the relatively slow transport speed.
An advantage of the invention, stated below, is to provide a device for stacking flat postal articles that stacks flat postal articles with minimum disturbance, upright on their narrow edges, in a continuous, edge-oriented stack, regardless of thickness, rigidity and format.
The wire-shaped, centrically arranged, helical coils, fastened to the rotatable receiver, into which the fingers of the rake protrude such that the helical coils can turn in the gaps, with the individual postal articles being transported into the gap between the helical coils of a course and, standing on the fingers, being pushed through the rotating helical coils to the support or to the stack of postal articles already standing on the base, mean that each individual postal article is held, slowed down and continuously moved on separately. All movements are thus definitely reproducible. The fact that the postal articles stand on the fingers at the height described means that the articles cannot become incorrectly entangled in the helical coils.
It is thus advantageous if the helical coils have a triangular cross-section and the cross-section is aligned relative to the direction of feed of the postal articles into the helical coils, so that sticking or entanglement of bent or kinked postal articles in the helical coils is largely prevented.
In order to be able additionally to guide the largest postal articles safely, the height of the outermost helical coils above the fingers advantageously corresponds almost to the height of the largest postal article.
In a further advantageous embodiment, the individual postal articles are fed from above into the area of the course of the helical coils, in that the movement of the helical coils is directed toward the supporting wall and/or the base. The effect of this is that the postal articles are aligned toward the fingers and supporting wall due to the frictional driving forces at the helical coils.
To prevent a rebound of the postal articles from the fingers at high injection speeds from above, the fingers are advantageously provided with an impact-absorbing surface.
It is also advantageous if the base is designed as an under-floor conveyor which together with the support is displaced away from the stacking point corresponding to the thickness of the particular postal article to be stacked. This correspondingly relieves the load on the helical coils.
In a further advantageous embodiment, the support is not actively driven, but instead is pressed with the aid of a spring element against the stack of postal articles over the complete movement path. In conjunction with a non-driven base, this results in a very cost-effective design.
In order to further reduce the feed forces required to form a stack, it is advantageous to disengage the fingers using narrow circulating belts, which can be synchronously driven by the under-floor conveyor of the base and also operated without a drive to reduce the coefficient of friction.
An additional advantage of the present invention lay in an apparatus for stacking articles in a stack, comprising a base comprising a top surface for supporting said a first side of said stack, said top surface comprising a rake formation comprising a plurality of adjacent fingers defining openings through said top surface between said fingers; a rotatable receiver vertically mounted proximate to said fingers and openings, said receiver comprising a plurality of substantially concentric vertically displaced coils, running in said openings, adjacent vertically displaced coils in cooperating with said fingers defining a vertical opening between said coils; a supporting wall for providing support to a second side of said stack, said wall abutting said base; and a support for supporting a third side of said stack, said support functionally associated with said base so as to be displaceable along said base in a direction of said stack.
Other features and advantages of the present invention will become evident from the specification and claims below.